1. Field of The Invention
The invention concerns a movable connecting device between a supporting element and a supported element. The invention applies to the field of robotics, to the design and manufacture of manipulator arms.
2. Description of The Prior Art
The French patent application 82,21389 describes a differentially acting connecting device which includes:
a supporting framework designed to be fixed on the bearer element, PA1 a movable framework designed to allow fixing the borne element PA1 a plurality of flexible jacks arranged between the bearer framework and the movable framework so as to keep said movable framework and said bearer framework in a relative position depending on the set of deformed states of said flexible jacks. PA1 a variable-capacity reservoir associated with each of said flexible jacks and forming with the particular jack a closed fluid circuit so that the capacity of said reservoir constrains the deformation state of the flexible jack, each set consisting of a flexible jack and a variable-capacity reservoir being associated with second set consisting of a flexible jack and a variable-capacity reservoir in order to form a differential system. PA1 a drive varying the capacity of the above cited reservoirs to set them to specific values and arranged to simultaneously drive two reservoirs associated in such a way that their capacities vary inversely, the two associated flexible jacks undergoing opposite deformations, PA1 measuring means associated with each flexible jack and designed to emit a signal representing the deformation state of the said flexible jack. PA1 a processing unit arranged to receive the signals emitted by the measuring means associated with each flexible jack and designed to emit differential signals for each pair of associated flexible jacks representing the difference between the deformation states of the two jacks of said pair, PA1 a set-signal generation unit designed to emit set signals corresponding to the desired deformation states of the pairs of flexible jacks, PA1 a comparison unit arranged to receive the above cited differential signals and the set signals and designed to emit the error signals PA1 a controller for the above cited drive means and arranged so as to receive the error signals and designed to control the drive in the sense of nulling error signals.